This article introduces one of the most important topics in WordPress development: WordPress hooks, including action hooks and filter hooks. They are at the core of not only how WordPress plugins work, but nearly all code throughout the WordPress ecosystem. By that I mean most WordPress themes also use them. As does “WordPress core” itself. WordPress hooks are kind of the *must know* topic in WordPress development.

This course covers one of WordPress’s most crucial and widely used systems: Hooks, including both actions and filters. We introduce Hooks as an event-driven system, present the key concepts and terminology you need to understand this system, and dig deep into how to use hooks in your own code—including hooking in your own functions, removing previously hooked functions, and creating your own action and filter hooks for others to use.

How does a single plugin become the basis of a thriving technology ecosystem? Partly by leveraging the extensibility that WordPress’s event-driven Hooks system makes possible.

WordPress’s hook system is an example of an “event driven” architecture or programming system.